The field of the disclosure relates generally to cooling systems, and more particularly, to a cooling system for use in regulating a temperature of components of a machine.
At least some known gas turbine engines include a combustor, a compressor coupled upstream from the combustor, a turbine, and a rotor assembly rotatably coupled between the compressor and the turbine. Some known rotor assemblies include a rotor shaft, at least one rotor disk coupled to the rotor shaft, and a plurality of circumferentially-spaced turbine blades or buckets that extend outward from each rotor disk.
During operation of at least some of such turbines, the compressor compresses air that is subsequently mixed with fuel prior to being channeled to the combustor. The mixture is then ignited generating hot combustion gases that are then channeled to the turbine. The rotating turbine blades or buckets channel high-temperature fluids, such as combustion gases, through the turbine. The turbine extracts energy from the combustion gases for powering the compressor, as well as producing useful work to power a load, such as an electrical generator, or to propel an aircraft in flight.
At least some known turbine blades include an airfoil that includes a pressure side and a suction side that are connected together along leading and trailing edges. Each airfoil extends radially outwardly from a dovetail that is used to mount the turbine blade to a rotor disk or spool. During operation, the leading edge portions of at least some known turbine blades are generally exposed to higher temperatures than the trailing edge portions. At least some known blades are hollow and include an internal cooling cavity that is defined at least partially by the airfoil and dovetail. Cooling fluid is channeled within the cavity in a random flow pattern that may create temperature variations throughout the turbine blade and that may create an uneven heat transfer between the turbine blade and the cooling fluid. Such temperature variations may induce compressive thermal stresses to the airfoil. Over time, continued operation with high compressive thermal stresses may lead to airfoil cracking, and/or airfoil deflection, any or all of which may shorten the useful life of the rotor assembly.